S t. Charles Civil Parish was fourth on the list of the nineteen original parishes that were simultaneously created out of the Territory of Orleans by Act I of 1807. Act I made no attempt to do more than merely list parishes, except, perhaps in a very limited venue, to convey some semblance of their general locality. Prior to 1807, the so-called “parishes” were neither political nor legal subdivisions of the state, but mere ecclesiastic vicinities. Act I lifted St. Charles and the other parishes it created out of the status of ecclesiastic vicinities to the category of legal and official political subdivisions of the Territory of Orleans. Initially, the eastern boundary (the city of New Orleans) was purported to be fixed as the eastern boundary of St. Charles until 1825 when Jefferson Parish was created out of the western portion of the Parish of Orleans. (Information extracted from a report on the boundaries of St. Charles Parish by Research Engineer Gervais Lombard, December 5, 1939, prepared for the Louisiana Department of Public Works.)

According to Cecil Morgan, dean emeritus of the Tulane University School of Law, in his narrative The First Constitution of the State of Louisiana, published by the Historic New Orleans Collection, the governing body of the parish was not set up in the first constitution, but the term police jury evolved by custom and the enactment of a series of territorial acts involving a novel use of the newly formed jury. Dean Morgan said a “jury” would be empanelled, often to do a specific job for the county or community, such as building a courthouse, bridge, or jail. Other duties followed, such as establishing a gendarmerie (police force) first to retrieve fugitive slaves, then as a regular parish police force, and later as a group to do things for the parish or county under the jury. Eventually, the “police jury” emerged as the parochial governing body.